If you are disciplined, I think you can get 80-90% of the results of a prep course through self study.
If you are considering this, the question to ask yourself is whether 1-3 points is worth that money. 1-3 points could make major differences in your law school chances, it really depends on where you want to go.
Live courses give you a chance at having a professional watch you and work with you directly. The other option would be to study yourself, but drop $400-$500 on a tutor. Either option will get you the results you want. At the end of the day, the tutor is cheaper, the course is easier.